Derek, I'll take a stab at it, and others can add and/or correct if I
go astray.
Flywheel weight runs from about 36 lbs for the stock, cast, 164 tooth
flywheel to about 12 pounds for the aluminum 157 tooth racing
versions. You would feel a marked difference in the way your Tiger
responds to throttle inputs between those two.
Keep in mind also that there is about a 1 inch difference in diameter
between the two, and that this plays a role as well. Angular inertia
is calculated as the weight times the square of the radius (or
diameter -- I don't have the formula with me). Regardless of whether
I have the formula right, it boils down to the notion that reducing
the diameter of the flywheel, even if it were the same weight, would
result in less rotational intertia.
One other thing -- factory bellhousings are made for a particular
flywheel diameter. Use a 157 tooth flywheel with a 164 tooth
bellhousing, and your starter won't engage the flywheel.
Aftermarket "blowproof" bellhousings usually have provisions to
position the starter for both diameters.
So, my recommendation? I'm basing this on my experience with a '65
Mustang with a similar motor and about 300 lbs more curb weight than
your Tiger (as the Tiger resto is still in progress). The extra
weight was probably more than offset by the wide-ratio Toploader and
3.07 rear gears.
The best compromise for me was a 157 tooth billet steel version like
those available from McLeod, FMS, and others. The 24 lbs that it
weighs, combined with the smaller diameter, give it good response
without screwing up the idle too much (as Steve observed). I have
one for the Tiger, but I won't be able to tell you how it works out
until next spring.
I stay away from the aluminum versions. A misadjusted clutch or
extra-rowdy driver can heat one up and warp it, resulting in serious
clutch chatter. I'm not a big enough fan of pulling motors out of
Tigers to go that route. They can also be too "snappy" for some
people.
My final cautionary tale is that rotating mass and inertia are good
things when it comes to balance and therefore engine life. The big
flywheel contributes by damping vibrations more effectively than
smaller, lighter versions. Tradeoffs, tradeoffs, tradeoffs.
Brian
--- Original Message ---
From: "Derek White" <derekw@coppernet.zm>
To: <SLaifman@SoCal.RR.com>, "Tiger List" <tigers@autox.team.net>
Subject: 302 flywheel weight??
>Hi Steve,
>
><snip>
>I understand all the flywheel issues you brought up. Surely someone
has
>addressed this issue before? I am sure that the std 302 flywheel is
designed
>to work well in heavy US cars and there should be someone who has
figured
>out the best weight for a tiger given its weight, 1st gear and diff
ratio.
>SOMEONE OUT THERE PLEASE HELP!! I tried looking on tigersunited but
the
>server is still down.
>
>cheers, derek
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